This paper reports on the synthesis of a novel poly(ethylene oxide) (PEO) macromonomer, which can be copolymerized with epsilon-caprolactone (epsilon-CL) by ring-opening polymerization (ROP). PEO chains ... [more ▼]

This paper reports on the synthesis of a novel poly(ethylene oxide) (PEO) macromonomer, which can be copolymerized with epsilon-caprolactone (epsilon-CL) by ring-opening polymerization (ROP). PEO chains end-capped by an epsilon-caprolactone unit (gammaPEO(.)CL) have been synthesized by living anionic ring-opening polymerization of ethylene oxide (EO) initiated by the potassium alkoxide of 1,4-dioxaspiro[4.5]decan-8-ol, followed by derivatization of the acetal into a ketone and the Baeyer-Villiger oxidation of the ketone into a lactone. The end-capping of PEO by epsilon-CL was assessed by FTIR, MALDI-TOF, and H-1 NMR spectroscopy. This type of macromonomer is a precursor of amphiphilic comblike copolymers consisting of a biodegradable hydrophobic backbone of poly-(epsilon-caprolactone) (PCL) and hydrophilic PEO grafts. Copolymerization of gammaPEO(.)CL with epsilon-CL was successfully initiated by aluminum alkoxide. [less ▲]

POly-DL-lactide end-capped by a protected thiol was synthesized by bulk ring-opening polymerization (ROP) of DL-lactide initiated by the reaction product of aluminum isopropoxide [Al (iOPr) (3)] with ... [more ▼]

POly-DL-lactide end-capped by a protected thiol was synthesized by bulk ring-opening polymerization (ROP) of DL-lactide initiated by the reaction product of aluminum isopropoxide [Al (iOPr) (3)] with alpha- (2,4-dinitrophenylsulfenyl) ethanol. After the thiol deprotection, PLA-SH was used to stabilize gold nanoparticles. Either these nanoparticles were prepared in the presence of PLA-SH, or PLA-SH was substituted for part of the undecanethiol (C11SH) that stabilized preformed gold nanoparticles. In contrast to C11SH-coated nanoparticles, those stabilized by PLA-SH were successfully entrapped into 100-nm PLA nanocarriers prepared by nanoprecipitation. This is an easy technique to label PLA biocarriers and therefore trace their fate in vivo. [less ▲]